Which type of gas water heater tank makes the most sense (venting related question)

Discussion in 'Water Heater Forum, Tanks' started by indigo, Dec 18, 2013.

  1. indigo

    indigo New Member

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    Ok, this is kind of complicated, but try to bear with me. I've got an old house, built in in the 1920s and it has 2 chimneys. Presently, 1 vents the boiler and 1 vents the hot water heater. Both are atmospheric vents, both appliances are in the basement. However, as part of replacing the roof, I am planning on removing the chimney that the water heater is connected to. The chimney has deteriorated and is in need of repair, but I don't think it's worth it just to vent a water heater in that location, and it's a very poorly placed chimney that will make the new roof install unnecessarily complex. Both chimneys have clay liners. I will then have the hot water heater replaced and relocated to near the boiler.

    My original thought was to tie the a new atmospheric water heater into the flue of the boiler. Apparently this is a no-no, however. So, a power vent water heater which would vent through a very nearby wall was suggested. However, I am concerned about no hot water during a power outage. Then I began looking at a non-powered direct-vent as an option, but that was recommended against as obsolete and inefficient. And of course there are powered direct-vents, though I can't really tell when one would use that over a regular power vent. Or I could maybe look into relining the chimney the boiler and water heater tie into, difficult part of this is that the house and chimney is very tall, and has put off a few masons in the past.

    So, here's the question, what's the best option?

    a) non-powered direct vent (possibly inefficient)
    b) power vent (no power, no hot water, more moving parts)
    c) powered direct-vent (no power, no hot water, more moving parts)
    d) atmospheric, get the chimney relined (cost and difficulty of the relining)
    e) some other option I haven't thought of?

    For whatever it's worth my plumber prefers Bradford-White.

    Finally, does anyone have experience with providing some sort of backup power to a power vented water heater. I suppose this is a similar challenge faced by those with tankless units?

    Oh, one other thing, how loud are the power vented water heaters? I've got a living room right over where the boiler and water heater will be and there's not much in the way of insulation in the floor, so this is a mild concern. Is most of the noise in the room from the blower itself or is it outside where the exhaust pipe exits?
    Last edited: Dec 18, 2013
  2. Dana

    Dana In the trades

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    f) Install in indirect-fired hot water heater operated as a separate zone off the boiler, and set it up with a heat-purging economizer type control. (Assuming the boiler is gas fired and at least 80% AFUE.)

    [​IMG]

    The increased load and higher duty-cycle on the boiler improves the net efficiency by reducing the standby loss of the boiler. A heat purge control (eg Intellicon 3250 HW+) draws the temp of the boiler down after a burn dumping that heat from the hot boiler into the indirect tank (or heating zone) rather than giving it up as standby loss, reducing the losses even further. A decent indirect should give you at least a couple decades of low-maintenance service, and will deliver far more hot water than a typical standalone tank. During the heating season it operates at essentially the same efficiency as the boiler. (80%+) During the summer it'll run at about the same efficiency as a standalone hot water heater.(55-60% with an 80% AFUE boiler). The higher efficiency the boiler, the better the hot water heating efficiency.

    For more detail than you probably ever wanted to know see this document:

    http://www.nora-oilheat.org/site20/uploads/FullReportBrookhavenEfficiencyTest.pdf

    For the short-story scroll down to table #2- only system #3 has a heat purge control, but if you compare the steady state efficiency vs summer hot water between system #3 and system #2 (the only other indirect tank system tested in that report), you see how important the heat purge control is for summertime efficiency. The heat purge control is an ~$200 cost-adder if installed when the whole thing is put together (more, if done as a separate job), but it'll pay for itself in fuel savings just on the space heating end in only a heating season or two.

    The reason the chimney serving only the hot water heater is falling apart is almost certainly due to it's serving only the HW heater. This is sometimes referred to as the "orphaned hot water heater" problem. The BTU-output of a hot water heater is so low that almost all masonry flues are ridiculously oversized for it. The high thermal mass of the masonry plus oversized flue means that the flue liner never heats up, and the mildly-acidic natural gas exhaust condenses on/soaks into the masonry, breaking down the mortar, a handful of years later the thing looks downright pitiful.

    If the flue handling the boiler is big enough to take both the boiler & HW heater, a wye-connection joining them together at the entry point to the masonry usually works, and would likely be your cheapest way out.

    It's common to add a stainless liner inside a deteriorating terra-cotta lined flue rather than trying to repair a terra cotta liner. With mid-to-high-efficiency oil fired boilers stainless liners are now the standard way to go even if the terra cotta is in good shape, since the higher the efficiency, the lower the stack temp, and the more exhaust condensation you get. Oil exhaust is considerably more acidic than natural gas exhaust, so getting right-sized (for the BTU-output) corrosion resistant liner is the best insurance. It's not cheap, but it's WAY cheaper than rebuilding a chimney. If the flue liner is a lot smaller than than the prior terra cotta flue (common, if they right-sized the boiler for the heat load) it's also common to fill the space with blown rock-wool insulation, which improves draft velocity and raises the temp of the liner above the dew point of the exhaust more quickly.
  3. indigo

    indigo New Member

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    14
    Location:
    Pittsburgh
    I had thought briefly about the indirect option... but that might just be the way to go. Probably a couple stumbling blocks. I have a single-zone nat gas system now, boiler is from the early 80s -- probably not 80% efficient, but it's not in the budget to be replaced. To add an additional zone what would be required? An additional circulator pump?

    As for loss of power, my understanding is that the indirect tanks are very insulated so that might mitigate that problem a bit.

    Orphan water heater: I had read about that, but hadn't thought it through that it could be causing my existing problem. I had been thinking about it in the context of not causing that problem in the new location's chimney.

    Thank you for the thorough response!
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Some of the better IWH are rated at as little as 1/4-degree/hour temperature drop. Some also are available in SS, which often have a lifetime warranty. Adding a zone is often fairly simple...various companies make zone controllers, Taco for one. It depends on how the boiler is setup whether you would need a second circulator or not. OFten, it is setup as a priority zone, so it gets all of the heat when it needs it to keep it hot. This allows the tank to be smaller than you may need with a self-fired tank (your boiler is almost certainly a lot larger than the typical gas WH's burner).
  5. Dana

    Dana In the trades

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    Most early 1980s boilers were typically 78 AFUE, but had a steady-state combustion efficiency of about 80-81%. The derating for AFUE was due to the standing-pilot ignition. If the nameplate indicates a D.O.E. output BTU number that is 80% or more of the input BTU indicatec, that's good enough. (Some boilers going back to the 1950s would still cut it, but not all.)

    Indirects will nearly always need their own circulation pump (a Taco 007 is probably most typical). If the boiler output is rated over 120,000BTU/hr it can be controlled as a generic zone and you'll never even know when the other zones kick on/off, but if it's output is much under 100,000BTU/hr it's better to use zone controller that supports a "priority" zone as Jim suggests. When the priority zone calls for heat the controller suppresses calls for heat from the other zones until the priority call is satisfied. If you make the indirect the priority zone it will get 100% of the boiler's output. If the output is somewhere in between 100-120K, you can still do it without the priority control, with the understanding that if all zones are calling for heat the recovery time on the indirect will be slower.

    As Jim points out, all but the very smallest boilers will have more output than a typical 40-50 gallon standalone, and most have significantly more output than that, so you can usually down-size the tank volume a bit (say from 50 down to 35-40 gallons), and still be serving up more hot water than the standalone.

    A boiler than is 30 years old is usually pretty close to end-of-life. Rather than blindly replacing it with one the same size the week it fails, it's good to have your replacement plan already worked out in advance. Most existing boilers are ridiculously oversized for the actual heating loads, and you'll get more comfort and efficiency out of a boiler that is no more than 50% oversized for the space heating load if you can. AFUE is tested at a presumptive 1.7x oversizing, but the real world installations are more often than not 2-3x oversized for the loads. In those typical cases, even at the 99% outside design temp they run at something like a 30-50% duty cycle, and at the average winter temp it's a 10-15% duty cycle, which means the fraction of the heat that went into standby losses is large.

    As outlined in that Brookhaven National Laboratory boiler modeling study, a heat purge controller can pull the efficiency back quite bit toward it's steady-state efficiency, but not all the way. If the next boiler is better matched to the space heating load, it'll do much better on efficiency, and rather than rapid heat-up with overshoots, followed by a cool undershoot, the boiler's duty cycle will be longer, and room temps steadier.

    It is 7th grade napkin-math to size the boiler correctly using the existing boiler as the measuring instrument, if you have a mid-winter fuel bill with the exact meter reading dates, which makes it possible to correlate the fuel use to the heating degree-days that occurred between the dates. If you want to figure out just how oversized your existing boiler is, I can show you how that's done. (Or you can just follow the examples on other threads on this forum.)
  6. indigo

    indigo New Member

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    Location:
    Pittsburgh
    I will have to go through and study Dana's latest post more carefully, quite the wealth of information this forum is proving to be!

    But one overall question: If I go indirect and add the necessary components to a second zone today to my current boiler, how much of that would/could carry over to a new boiler install?

    As for boiler size, if memory serves, the current is around 165k BTU and actually does a pretty solid job at keeping the house comfortable with a steady temperature. Note that we're talking 3 floors poorly insulated by modern standards. I will run through the calculations though to see how over-sized it is.

    EDIT: looks like 78% (DOE / Input) Also, any thoughts on the Hydrotherm R-210B in general? Predates my ownership and doesn't look like there's much commentary online about it... which is either good or bad...

    A pic of the plate:
    IMG_20131129_185950.jpg
    Last edited: Dec 19, 2013
  7. Dana

    Dana In the trades

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    Yup, at 164K out with 210K in, that's a 78% boiler- which is good enough as long as it's in good shape. With 164K of output you absolutely DON'T need to run the indirect as a priority zone, since your heat load is nowhere near even HALF that (unless it's an 8000 square foot mansion or something.)

    But also at 164,000 BTU/hr of output it's probably around 3x oversized for your actual heat load, and probably running in the low to mid-60s for efficiency due to high standby loss. With a heat-purge controller you'd be able to bring that up into the mid-70s saving on the order of 12-15% on your heating fuel use.

    If/when you replace the boiler with something more appropriately sized for the heat load, keeping the indirect is no different than keeping your other heating zones. But when you down-size you will likely want to install a zone controller that can set up the indirect as the priority zone.

    Lowering the heat load of the house with air-sealing and spot-insulating is usually cost-effective on 1920s houses- it usually doesn't take a heluva lot to cut the heat load by 25-30% or more. On 3-story homes with a full basement you have a HUGE "stack effect" driving infiltration, and air sealing at the upper floor ceiling as well as the basement (and any flue/utility chases or empty balloon framing that runs from the basement to the attic uninterrupted) can cut your average infiltration losses by more than half, even if you don't bother air-sealing the intermediate stories. If you take out the second chimney completely, seal up the abandoned chase at every floor with a sheet of OSB, mastic or foam sealed to the subfloors, etc. If you leave some or all of it, be sure to brick up and seal all of the unused ports for water heaters/boilers etc.

    Most basements of that era leak like sieves, and have no insulation- the largest ignored and untreated air leak in most houses is the long skinny one between the top of the foundation and the foundation sill (a bigger hole than all window & door crackage combined.) Even if you aren't finishing the basement into fully conditioned space, the heat losses are usually a double-digit percentage of the total if uninsulated, and insulating correctly will reduce basement moisture/mold issues. Insulating basements can be tricky, with methods that are climate-specific to get right. Done wrong they can mold-inducing , so read up on it (or check back) when you're ready to head down that road.
  8. Raspy

    Raspy New Member

    Messages:
    11
    Location:
    Northern Nevada
    The problems with an indirect in your case are that you are not increasing the efficiency of your system, the cost for the indirect and related equipment is much higher than a conventional water heater and you seem to be worried about hot water during power failures. The indirect won't work during power failures, but you would still have some stored water.

    I don't like hooking up new indirects to old boilers of that type. Everything get disturbed and a lot of labor goes into an old machine with possibly limited life remaining, plus the system will be even less efficient when you are not heating and you still have to heat all the mass of that boiler just to make hot water. Maybe it's time to upgrade to a condensing boiler and indirect. Or find a way to install a cheap conventional water heater or one with a direct power vent.
    Last edited: Dec 23, 2013
  9. Dana

    Dana In the trades

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    Installing an indirect along with heat-purge boiler controls DEFINITELY increases the efficiency of the system!

    Trust the people at Brookhaven National Labs who actually measure & model this stuff:

    http://www.nora-oilheat.org/site20/uploads/FullReportBrookhavenEfficiencyTest.pdf

    See table 2, systems #2 & #3: When serving hot water only system #2 delivers only about half it's steady state efficiency. But with a retrofit heat purge control it will behave more like system #3, and in hot-water heating only mode deliver on the order of 80% of it's steady-state efficiency. (See Table 3 system #2 for an assessment of what it's operational efficiency in space heating mode is at 3x oversizing- that's probably where we are, or maybe even a bit worse with this beast.)

    That means with a heat-purge controller a 78% steady-state boiler will run about 60-65% efficiency in hot-water-heating-only mode, which is better than most standalone tanks, and adding the extra load to this ridiculously oversized boiler improves it's useful duty cycle. With the boiler heat-purging into the zones at the beginning/end of each burn cycle, the reduced standby loss improves the as-used efficiency of this beastie boiler from the 60-65% range to something close to 75% in space-heating mode.

    Sure, it's not the same efficiency uptick as installing a right sized condensing boiler to the tune of $10,000 or better. But it's a $200 investment, an investment that will typically pay for itself in one heating season or less when the boiler is 3x or more oversized for the space heating load (at it almost surely is), and probably enough fuel savings just on the space heating end to cover the entire domestic hot water heating fuel use.

    When it's time to replace the boiler, the indirect will still have plenty of life left, and can be used with any type of boiler.
  10. Raspy

    Raspy New Member

    Messages:
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    Location:
    Northern Nevada
    Maybe you see something I don't, but the Brookhaven test you cite confirms an indirect with purge control is only 74.9%. for a steel boiler. Cast iron in the summer with indirect at 38.3%. Purge control on DHW systems can only help so much because the purge temp cannot go lower than the DHW temp. Efficiency varies based on the time between cycles because that influences standby losses. If the system sits long enough that the boiler cools to room temp, the cost of operation has to include warming the mass of the boiler and that energy being lost between cycles. This lowers effective efficiency by a variable amount that is not such a big factor in a tank type water heater by comparison. Either design has a low mass storage tank included. The indirect has lower loss than a conventional water heater, but a conventional water heater has lower loss than an old cast iron boiler. Your conclusions, based solely on charts, are a good starting point, but we also have to look at the existing equipment, it's condition and the homeowners wants and needs.

    When there is no call for heat, or in the summer time, you do not increase efficiency by purging heat into one of the heating zones. You are just sending it to a place you don't want it instead of up the vent.

    The efficiency of the indirect on an old iron boiler is about the same, depending on cycle times, as a conventional water heater, but has a much higher initial cost to set up and won't work in a power failure. Plus it relies on an old boiler that may have limited life going forward.

    Indirects are not always a good solution when you factor in real world efficiency with old boilers, initial cost, hot water consumption and homeowners requirements. Better to look at it on a case by case basis. For instance, in this case, the OP wants hot water during power failures.
  11. Dana

    Dana In the trades

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    The heat purge temp on the steel boiler#3 at the end of water heating only burn never went below 140F, which is the low-limit operation of that boiler (EK Sytem 2000), though it was allowed to purge to 104F on new calls for heat before re-firing. (see Appendix 3). With a gas-fired boiler you can drop that to 130F without risk of damaging condensation, and you can set it up for cold-starting (unlike many old cast iron oil boilers.)

    The boiler #2 ran at 38% in hot water only mode (instead of it's 78% steady-state efficiency) BECAUSE it didn't have heat purge controls. A the end of the call for heat the boiler is at 180F or higher, and was not allowed to drop below 150F during standby (see the details in Appendix 2). The the very reason why adding a heat purge controller to the boiler will dramatically improve both water heating and space heating efficiency performance is that it doesn't park the boiler at 180F at the end of a burn, abandoning all that heat. With a cold-start gas boiler it gets even better- with a lower purge temp, and allowed to drop below the operation low limit between calls for heat. Lower boiler temp= lower rate of loss.

    Boiler #3's steady state efficiency is about 88%, and with heat purge control, buts still heats the water at 74.9% due to the low standby loss of the boiler. That standby loss is low because the boiler's higher-temp heat is purged into the tank (not another zone) to the storage temp at the end of the burn, and allowed to purge as low as 104F before re-firing during a new call for heat from the indirect. (See Appendix 3). That much lowering the temperature of the boiler slows the standby loss rate, and the total amount of energy abandoned in the boiler, and allows the indirect to purge any remaindered heat until the boiler reaches 104F during a new call for heat.

    Retrofit heat purge controllers also anticipate the end of the call for heat from indirects cutting the burner (but not the pump) early, and DO purge the boiler heat into the tank, parking the thermal mass of the boiler at something like 140F instead of 180F. All gas boilers (and some oil boilers) can be set up for cold-starting rather than keeping it at some minimum temp over the summer. While setting it 104F would be on the low side for even a cold-startable cast iron gas boiler, 130F is totally safe, (even 125F is safe if the flue isn't oversized and prone to flue condensation) but the 50F difference between 130F and 180F is enough to make a radical difference in both the standby rate loss between burns, and the total amount of heat abandoned in the boiler for extended off-periods where the boiler's temp falls well below the operational low-limit or DHW temp.

    So, with retrofit heat purge controller and setting it up for cold staring the hot-water-only performance of an old gas-fired boiler won't be identical to the steel boiler #3, but it'll be pretty similar in proportion to it's steady-state vs. water heating only efficiency. It's certainly no worse than a center-flue standalone tank during and FAR better than a cast iron boiler like #2 maintained at 150F between burns, without heat purge. And during the 8 months of heating season with heat purge it'll do about 75% efficiency with the combined heating + hot water load, which beats the socks off a standalone tank (and comparable to a big-burner tankless hot water heater), as opposed to about 65% without the heat purge control.
  12. houptee

    houptee Member

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    186
    Location:
    Monmouth County, NJ
    That boiler will last a lot longer no need to replace it.
    It has a standing pilot correct?
    Simple, reliable, and inexpensive to fix what else would you want?
    The cost to replace it vs. the time to recoup that cost in energy savings is ????
    Insulate the house better if you can.

    Put in a tankless water heater (my personal preference Takagi TKjr2) vent it directly out the wall with approved stainless venting.
    Tankless use such little electricity that you might be able to get a UPS power supply to power it for several hours instead of a generator.
  13. indigo

    indigo New Member

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    14
    Location:
    Pittsburgh
    Still weeding through the rest of this thread, but yes, standing pilot. I'm not really planning to replace the boiler unless it fails, though I do plan to have a plan in place for when that day comes. But, I am interested in potentially improving the current unit's efficiency so adding on the indirect or perhaps at least the heat purge control are on the table.

    Concern with a tankless unit here is a) we have very hard water and b) some concern over how long it will take to get hot water through the house (there's a tub on the 3rd floor, for example). And yes, I've looked at the potential for a UPS option, that would apply to a powervent unit as well it would seem.

    Regardless, current status is that I'm having someone in on Friday to take a more serious look at the status of the chimneys, relining and whether that's going to be a valid path to take or not. I will report back.
  14. houptee

    houptee Member

    Messages:
    186
    Location:
    Monmouth County, NJ
    The tankless isolation/install valves (several comapanies now make them) have built in flushing caps to connect garden hose type connectors.
    Once a year or sooner you flush the heat exchanger for scale buildup.
    3rd floor hot water will take a while even with a regular tank or indirect tank.
    You could install a recirculation pump to solve that but the extra cost of that vs. just waiting for 1min for the hot water is???
    On my second floor I timed it and it takes less than 1 min to get hot in the kitchen sick on full blast so its much faster than you would expect.
  15. Dana

    Dana In the trades

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    Adding a tankless Takagi won't be dramatically more efficient than an indirect running off the old boiler, and less efficient than running the indirect off a correctly sized modulating condensing boiler. It would also most likely require upgrading the gas service/meter to the house to handle the combined load of the old boiler and the Takagi Jr, which together add up to 350,000 BTU/hr, plus whatever gas-burners you might have (oven, range, etc.).

    An 0.82-0.84 EF tankless runs about 70% efficiency in real-world applications due to the short-cycling losses. The D.O.E. EF test uses only large multi-gallon water draws, never the 1-2 quart hand rinse, and are more reflective of the efficiency during showers or tub fill draws, not dish/clothes washer nor hand-rinse type draws. The flue-purge & ignition losses are the same whether drawing 25 gallons or 2.5 ounces. Those losses are a tiny fraction of the former, a large fraction of the latter, and a typical house sees between 20-30 hot water draws per day, most of them short-draws, which brings the efficiency average down.

    There are a number of heat purging economizers out there that can work, most of which are pretty similar in function, and most are DIY-able if you are reasonably handy, and most are under $200 at internet-street pricing. Look up the installation & operational manuals to parse the details to figure out which one might work best for you.

    Hydrostat 3200

    Intellicon 3250HW+

    Beckett 7600 AquaSmart

    You can probably dig up YouTube tutorials on installing most of them too, if the documentation isn't clear enough for you. No rocket scientists are wasting their careers installing heat purging boiler economizers, but I wouldn't hand the job over to the average 15 year old. Some basic electrician skills are required, and you have to figure out your existing boiler's controls to know where to break into/bypass the necessary portions.
  16. houptee

    houptee Member

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    186
    Location:
    Monmouth County, NJ
    All that is true what Dana said.

    What size gas pipe comes into the house directly from the meter now?

    I only suggested the tankless since it can vent thru the wall (in the proper location from the ground, any windows, doors, intake openings etc per code) so his chimney issue is solved, and the cost can be very reasonable if ordered online and he installs it himself with PEX tubing.

    The indirect systems require a boiler running all year. That is a lot of thermal mass giving off heat in the summer inside the thermal envelope of the house, and heat rises. So your central a/c has to work harder to remove the heat coming off that chunk of cast iron or steel heat exchanger that has no insulation just a sheet metal skin on it.

    There are pros and cons to everything, so many variables, and no perfect solutions in this world.
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Location:
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    A modern boiler doesn't stay hot between calls for heat, and with a smart controller on an older one, you can park it at its safest low temp setting, so the heat load isn't huge...It's MUCH bigger with an in boiler heat exchanger...there, to get adequate hot water, the temp must be MUCH higher.
  18. Dana

    Dana In the trades

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    Even old school cast iron gas boilers don't generally need to be kept at temp unless the through-bolts have stretched. Most can be safely cold-started, and as Jim correctly points out, even if this one leaks if allowed to cool to 70F over the summer, setting the low-limit to 125-130F with a heat-purge controller the standby loss will be a fraction of that of a boiler that has to be kept a 150F+ to serve up hot water. Unless it's a known leaker when cool, setting it up for cold start is the right way to go.

    Running an indirect isn't the same as running an embedded tankless coil- there is no point to keeping it hot with an indirect. When the indirect calls for heat it doesn't take much time for the boiler to self-heat sufficiently to where it is hotter than the indirect, and actively heating. How long it take varies with the thermal mass of the boiler and it's water content, and if in practice you get a temporary dip in domestic hot water temp due to that lag you can just bump the aquastat on the indirect up by a few degrees so that the output never drops below 110F at the taps (tub-fill temp) during the initial firing.

    Cold-starting oil boilers that weren't designed for it is much more problematic than cold-starting old gas boilers, due to the much greater acidity of oil exhaust condensate relative to that of natural gas exhaust. Many gas fired boilers of the 1970s were already set up for cold start except when they were fitted with embedded hot water heating coils, (I'm not sure if that was common in the 1960s).
  19. houptee

    houptee Member

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    186
    Location:
    Monmouth County, NJ
    Doesn't the indirect tank have to maintain a minimum temp all summer even when no calls for domestic hot water?
    If you go away on vacation for 2 weeks its going to run the boiler every time the indirect tank cools below set-point correct?
  20. Dana

    Dana In the trades

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    Yes, if you leave the system on when you go on vacation, it'll keep the indirect at temp. The standby loss of an indirect is still VERY low compared to a standalone tank. The standalone tank has a center-flue heat exchanger that convects heat into the room constantly, whereas the indirect has only plumbing connections, and is more completely covered by insulation, since it has no burner. The boiler will cool off to near room temp between firings, but those firings will be every other day or so if there is no draw on the hot water heater, unless you've really screwed it up. Insulating all near-tank plumbing to at least R4 (including the cold feed and the boiler loop) ensures a very low standby loss.

    I turn off my system when I leave for more than a couple of days. If it's only 2 days it's still hot enough to be useful when I get back, but it doesn't take an extremely long time to bring it fully up to temp even if I've been gone for 10 days and it has cooled to near room temp.
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